1. Technical Field
The present invention relates to impact load reduction structures, and particularly, to an impact load reduction structure that reduces an impact load transmitted to a battery for driving an electrically-powered vehicle.
2. Related Art
Batteries installed in electrically-powered vehicles, such as electric vehicles and hybrid vehicles, require large capacity and have large weight. Therefore, an electrically-powered vehicle is normally provided with a battery frame for supporting a battery. For instance, the battery frame is provided in a large space under the floor of the vehicle cabin, and a plurality of batteries are collectively disposed within the battery frame. There is a demand for a technology for suppressing an input of a large external impact load when an electrically-powered vehicle is involved in a collision.
As an impact load reduction structure that reduces transmission of an impact load to a battery, for instance, Japanese Unexamined Patent Application Publication (JP-A) No. 2013-14276 proposes an electric-vehicle battery support structure that can reliably distribute a load input from the front section of the vehicle. This electric-vehicle battery support structure is provided with a protrusion that protrudes downward from the floor surface, extends in the front-rear direction of the vehicle, and supports batteries. The front end of this protrusion is coupled to the rear end of a front side frame. Accordingly, a load input to the front side frame from the front section of the vehicle can be transmitted and distributed to the rear of the vehicle via the protrusion.
However, in the electric-vehicle battery support structure in JP-A 2013-14276, a vehicle body frame, such as the front side frame, is securely fixed to the protrusion, which supports the batteries, from the front side. Thus, when the front section of the electric vehicle makes a collision, an impact load transmitted through the vehicle body frame is input to the protrusion at once, possibly causing a large impact load to be input to the batteries. In particular, since an impact load increases rapidly in an early stage of a collision, there is a demand for a technology for reducing transmission of the impact load to the batteries in the early stage of the collision.